Town's Kevin Kilbane slipped a pass between Lubo Michalik and Liam Cooper on 39 minutes and Roberts raced through the gap to slot into the bottom right corner.
The same move undid United again on 44 minutes when Kilbane put Roberts behind Michalik and Cooper, with the wide man again finishing into the bottom right corner.
Roberts then tried for a hat trick with an audacious 35-yard lob which dropped onto the roof of the net.
But Huddersfield's real match winner was arguably veteran keeper Ian Bennett, 39, who made a string of brilliant saves in the minutes before Town took the lead.
He first tipped away Michalik's 35-yard free-kick on 36 minutes and was up quickly to parry Francois Zoko's follow up shot.
The best save came two minutes later when Bennett produced a flying leap to tip away Zoko's goalbound volley after Craig Curran's mazy run and by-line cross.